A new low-cost security system called VibWrite could eventually use finger vibrations to verify users.

Eventually, the system could be used to open doors or gain access to appliances by simply touching a solid surface.

“Everyone’s finger bone structure is unique, and their fingers apply different pressures on surfaces, so sensors that detect subtle physiological and behavioral differences can identify and authenticate a person,” says Yingying (Jennifer) Chen, a professor in the electrical and computer engineering department at Rutgers University-New Brunswick.

An illustration of a finger touching a solid surface with a sensor to detect vibrations. The VibWrite system can be linked to three types of pass codes for user authentication. (Credit: the DAISY Lab/Rutgers)

The market for smart security access systems is expected to grow rapidly, reaching nearly $10 billion by 2022, the researchers write in a paper describing VibWrite.

The goal of VibWrite is to allow user verification when fingers touch any solid surface, the paper says. VibWrite integrates passcode, behavioral, and physiological characteristics. It builds on a touch-sensing technique by using vibration signals.

An experimental setup of VibWrite on a wooden table and door panel. (Credit: the DAISY Lab/Rutgers)

It’s different than traditional, password-based approaches, which validate passwords instead of legitimate users, as well as behavioral biometrics-based solutions, which typically involve touch screens, fingerprint readers, or other costly hardware and lead to privacy concerns and “smudge attacks” that trace oily residues on surfaces from fingers.

“Smart access systems that use fingerprinting and iris-recognition are very secure, but they’re probably more than 10 times as expensive as our VibWrite system, especially when you want to widely deploy them,” says Chen, who works in the university’s School of Engineering and is a member of the Wireless Information Network Laboratory (WINLAB).

VibWrite allows users to choose from PINs, lock patterns, or gestures to gain secure access, the paper says. Users can perform the authentication process on any solid surface beyond touch screens and on any screen size.

The system is resilient to “side-channel attacks”—when someone places a hidden vibration receiver on the surface or uses a nearby microphone to capture vibration signals. It also resists several other types of attacks, including when an attacker learns passcodes after observing a user multiple times.

A great benefit is that a VibWrite system is low-cost and uses minimal power. It includes an inexpensive vibration motor and receiver, and can turn any solid surface into an authentication surface. Both hardware installation and maintenance are easy, and “VibWrite probably could be commercialized in a couple of years,” Chen says.

During two trials, VibWrite verified legitimate users with more than 95 percent accuracy and the false positive rate was less than 3 percent. But the current VibWrite system needs improvements because users may need a few attempts to pass the system.

To improve performance, the team will deploy multiple sensor pairs, refine the hardware, and upgrade authentication algorithms. They also need to further test the system outdoors to account for varying temperatures, humidity, winds, wetness, dust, dirt, and other conditions.

The researchers’ will present their findings in a paper at the ACM Conference on Computer and Communications Security, a flagship annual event of the Association for Computing Machinery (ACM). Additional coauthors of the paper are from the University of Alabama at Birmingham.